'\" et
.TH MQ_SETATTR "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.\"
.SH NAME
mq_setattr
\(em set message queue attributes
(\fBREALTIME\fP)
.SH SYNOPSIS
.LP
.nf
#include <mqueue.h>
.P
int mq_setattr(mqd_t \fImqdes\fP, const struct mq_attr *restrict \fImqstat\fP,
    struct mq_attr *restrict \fIomqstat\fP);
.fi
.SH DESCRIPTION
The
\fImq_setattr\fR()
function shall set attributes associated with the open message queue
description referenced by the message queue descriptor specified by
.IR mqdes .
.P
The message queue attributes corresponding to the following members
defined in the
.BR mq_attr
structure shall be set to the specified values upon successful
completion of
\fImq_setattr\fR():
.IP "\fImq_flags\fP" 12
The value of this member is the bitwise-logical OR of zero or more of
O_NONBLOCK and any implementation-defined flags.
.P
The values of the
.IR mq_maxmsg ,
.IR mq_msgsize ,
and
.IR mq_curmsgs
members of the
.BR mq_attr
structure shall be ignored by
\fImq_setattr\fR().
.P
If
.IR omqstat
is non-NULL, the
\fImq_setattr\fR()
function shall store, in the location referenced by
.IR omqstat ,
the previous message queue attributes and the current queue status.
These values shall be the same as would be returned by a call to
\fImq_getattr\fR()
at that point.
.SH "RETURN VALUE"
Upon successful completion, the function shall return a value of zero
and the attributes of the message queue shall have been changed as
specified.
.P
Otherwise, the message queue attributes shall be unchanged, and the
function shall return a value of \-1 and set
.IR errno
to indicate the error.
.SH ERRORS
The
\fImq_setattr\fR()
function shall fail if:
.TP
.BR EBADF
The
.IR mqdes
argument is not a valid message queue descriptor.
.LP
.IR "The following sections are informative."
.SH EXAMPLES
None.
.SH "APPLICATION USAGE"
None.
.SH RATIONALE
None.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "\fImq_open\fR\^(\|)",
.IR "\fImq_send\fR\^(\|)",
.IR "\fImsgctl\fR\^(\|)",
.IR "\fImsgget\fR\^(\|)",
.IR "\fImsgrcv\fR\^(\|)",
.IR "\fImsgsnd\fR\^(\|)"
.P
The Base Definitions volume of POSIX.1\(hy2017,
.IR "\fB<mqueue.h>\fP"
.\"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
.PP
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
